Web stabilizing device

ABSTRACT

Means is provided for eliminating web flutter which is associated with the conveyance of a free web at high speeds. The means comprises a plate which is spaced relative to the web forming an acute angle therewith. The presence of the plate causes the air carried by the web to be collected in a small region thereby eliminating the turbulence associated with the free movement of the web.

United States Patent [1 1 MeAnespi et al.

[ 1 May 28, 1974 WEB STABlLlZlNG DEVICE [75] Inventors: Donald McAnespi, Quebec, Canada;

Robert Justin Laliberte, deceased, late of La Salle, Quebec, Canada by Carolyn Doris Laliberte, executrix [73] Assignee: Midland-Ross Corporation,

Cleveland, Ohio 22 Filed: Sept. 8, 1972 [21] Appl.No.:287,528

[30] Foreign Application Priority Data July 24, 1972 Canada 147773 52 us. Cl. 226/97 [51] Int. Cl B6511 17/32 {58] Field of Search 226/97, 7,- 95

[56] I References Cited UNITED STATES PATENTS 3,066,882 12/1962 Havens et al. .1 226/7 X 1/1966 Bader.....

3,227,017 226/7 X 3,273,775 9/1966 Cook 226/97 3,419,203 12/1968 Amend, Jr. 226/97 FOREIGN PATENTS OR APPLlCATlONS 1,176,027 1/1970 Great Britain 226/97 Primary Examiner-Allen N. Knowles [5 7] ABSTRACT Means is provided for eliminating web flutter which is associated with the conveyance of a free web at high speeds. Themeans comprises a plate which is spaced relative to the web forming an acute angle therewith.

The presence of the plate causes the air carried by the web to be collected in a small region thereby eliminating the turbulence associated with the free movement of the web.

2 Claims, 3 Drawing Figures vice relative to the web.

1 was STABHLIZHNG DEVICE BACKGROUND OF THE INVENTION In the conveying of a free web at high speeds the air movement in close proximity and relative to the web creates web flutter which when severe enough can break a weak web or produce a wrinkle in the processed web. As an example, in the drying of paper, sheet flutter can produce press or dryer wrinkles. In the drying of paper, the breaks cause production loss due to time in rethreading and wrinkles cause production loss through the formation of calender cuts or breaks on the winders.

The problem is often present with a free weak web, but becomes even more prevalent as machine speeds and widths increase. In the case of the drying of paper, several means have been tried to circumvent the problem with limited success. l Stabilizing rolls have been installed in the dryer pocket between adjacent dryer cylinders to stabilize the sheet in the draw between dryer cylinders. These rolls were approximately inches in diameter extending across the full width of the machine. While relatively successfulat minimizing the sheet flutter, they created an operating problem as the operators did not have proper access for the removal of broke. These stabilizing rolls, therefore, were inadequate. (2) When dryer wrinkles were encountered, attempts were made to alter the air flow about the sheet by opening and closing doors on the front and back sides of the hoods, to avoid the wrinkle forming. This is at best a haphazard approach and only temporarily solved the wrinkle problem, for the wrinkle can reappear at any time for apparently unknown reasons. (3) As a last resort the operator changed the loading and/or crown on the presses or adjusted the slice and increased the strength of the sheet at the edges by either increasing the weight of the sheet at the edges or increasing the dryness of the sheet. Again, these adjustments resulted in a nonuniform sheet entering the dryer section. This nonuniformity appears at the reel further reducing production and quality.

It is, therefore, an object of this invention to provide means for eliminating web flutter associated with the conveyance of a web at high speeds.

It is another object of this invention to provide means for eliminating the flutter in a free moving web which avoids the difficulty associated with fiber buildup.

It is a further object of this invention to eliminate web flutter without resorting to high velocity air streams.

BRIEF DESCRIPTION OF THE DRAWING vice incorporating the features of this invention; and

FIG. 3 shows in detailthe location of a stabilizing de SUMMARY OF THE INVENTION It has been discovered that placing a plate along each if the plate is so located that it forms an acute andgle with the moving web. The presence of the plate at an acute angle causes the air being carried by the web to collect in the apex formed between the stabilizer and the web to create a location of high pressure. Downstream from the apex the pressure tends to be reduced substantially and the effect on the web is insignificant.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the drawing, a web conveyor, such as a paper dryer, is shown generally at It and has a plurality of horizontally extending, evenly staggered dryer drums or rolls I2, and a plurality of upper and lower felt rolls M. A web supporting synthetic fabric 16 is conveyed about the upper rolls l4 and another fabric is conveyed on the lower rolls. A web 18, such as a paper web, is conveyed about the felt rolls 14 and intermediate the dryer rolls l2 and the web supporting fabric I6.

Located at various locations along the path of the web 18 are a plurality of web stabilizers 20. Each stabilizer comprises a cylindrical section 22 having an open end 24 and a closed end 26, and a plate having one end joining, as the drawing shows, approximately tangentially with section 22 The generally cylindrical wall of the stabilizer is extended as a lip 28 spaced in outward radial relation with that end of the plate 30 which 30 joins with the cylindrical section to form a longitudiedge of the web and in a position adjacent to the web will eliminate the flutter normally associated therewith nally extending opening or slot 32. Air supply means 34 is provided for supplying air under pressure into the open end of the stabilizer which air supply means may be variable.

The stabilizer 20 is positioned intermediately of a pair of rolls 12 in adjacent relationship along the path of the web l8, and in offset relation to such path, so that the plate 30, as it extends away from the section 20, converges with a portion of the web path extending in the direction of movement of the web (see arrows of FIGS. 2 and 3) to form an acute angle with the path and to define a converging region therebetween which terminates in a slot-like gap 35 between the distal end of the plate and the web during operation. As may be seen from the drawing, the slot is aligned in this position of the stabilizer to discharge air toward the converging end of the region between the plate and the web path. The presence of this stabilizer 20 causes the air being carried by the web 18 to collect at the apex formed between the plate 30 and the web 18. As this air builds up within the apex, it forms an associated pressure therewith which forces the web 18 away from the stabilizer 20. As the air escapes from the portion between the web 18 and the plate 30, the pressure will be reduced substantially thereby causing the air carried by the web to lose its fluttering effect.

The width of the web 18 will usually vary from approximately to 280 inches. It has been found that a stabilizer having an 18 inch length and spaced relative to each edge of the web is sufficiently large to'accomplish the function of eliminating web flutter. Although it is preferable to position stabilizers 26 only along the opposite edges of the web 18, if preferred, a single stabilizer extending the entire width'of the web 18 may be used.

Although it is the presence of the plate alone which eliminates the flutter of the web, it has been found desirable to maintain a warm flow of air along the surface of the plate 30. This flow of warm air prevents condensation from forming on the plate 30, and prevents the plate from touching the wet web 18. If the plate 30 were to touch the web 18, fiber particles would be picked up by the plate.

What is claimed is:

1. Apparatus for conveying fragile webs comprising:

between, said cylindrical section being generally enclosed except for said slot and an opening adapting it to connect with air supply means;

said stabilizer being positioned relative to said path so that the plate, as it extends away from said cylindrical section, converges with a portion of said path extending in the direction of movement of the web to form an acute angle with the path and to define a converging region therebetween terminating in a slot-like gap between the distal end of the plate and the web during operation, said slot being aligned by said positioning of the stabilizer to discharge air toward the converging end of said region.

2. The apparatus of claim 1 comprising: a plurality of said stabilizers of less width than said web and located adjacent opposite edges of the web. 

1. Apparatus for conveying fragile webs comprising: web advancing rolls spaced along, and defining, a web path; a web stabilizer for Eliminating flutter of a web transversely of said path located along said path in offset relation therewith intermediately of an adjacent pair of said rolls, said stabilizer comprising a cylindrical section and a plate having an end joining in generally tangential relation with said section, said section having a lip in radially spaced relation with said joining end of the plate to define a slot therebetween, said cylindrical section being generally enclosed except for said slot and an opening adapting it to connect with air supply means; said stabilizer being positioned relative to said path so that the plate, as it extends away from said cylindrical section, converges with a portion of said path extending in the direction of movement of the web to form an acute angle with the path and to define a converging region therebetween terminating in a slot-like gap between the distal end of the plate and the web during operation, said slot being aligned by said positioning of the stabilizer to discharge air toward the converging end of said region.
 2. The apparatus of claim 1 comprising: a plurality of said stabilizers of less width than said web and located adjacent opposite edges of the web. 